Sheet-gauging apparatus

ABSTRACT

Sheet-gauging apparatus for gauging properties of sheet material and having upper and lower gauging heads with timing belt means for precisely moving the gauging heads with respect to the sheet material.

Unite States Ptent Inventor App No.

Filed Patented Assignee Mathew G. Boissevaln Los Altos Hills, Calill.792,007

Jan. 17, 11969 Nov. 16, 19711 Measurex Corporation Santa Clara, Calif.

SHEET-GAUGING APPARATUS 13 Claims, 10 Drawing Figs.

us. Cl 250/833 10, 250/106 s, 250/219 TH Int. Cl

....... G2llh 5/00 Field 011' Search 250/83 D, 92, 106 S; 73/159References Cited UNITED STATES PATENTS Mamas Hansen Hansen et a1. Lehmanet a1.

Primary Examiner-James W. Lawrence Assistant ExaminerDavis L1 WillisAttorney-Flehr, Hohbach, Test, Albritton & Herbert ABSTRACT:Sheet-gauging apparatus for gauging properties of sheet material andhaving upper and lower gauging heads with timing belt means forprecisely moving the gauging heads with respect to the sheet material.

PATENTEBHuv 16 Ian 3,621,259

sum 1 or 6 INVENTOR Y Mathew G. Boissevain florneys PATENTEBNUY 1s |97l3,621,259

sum 2 OF INVENTOR Mathew G. Bar'ssevain PAIENIEUMW 1s I97| Fig. 3

SHEET 3 OF 6 INVENTOR.

Mathew G. Boissevain PATENTEBuuv 16 197i 31. 621 ,259

sum 0F 6 INVENTOR. Mathew G. Boissevain Attorneys PATENTEUHUV 16 mm3,621 ,259

sum 5 {1F 6 INVENTOR. Mathew G. Baissevain Attorneys BACKGROUND OF THEINVENTION Sheet-gauging apparatus has heretofore been provided. However,such sheet-gauging apparatus have had some disadvantages. For example,with such apparatus it has been difficult to precisely move the gaugingheads in a precise manner with respect to each other and with respect tothe sheet of paper being gauged. In addition, it has been difficult tomaintainthe necessary desired precise positioning of the gauging headsduring movement of thesame. There is, therefore, a need for a new andimproved sheet-gauging apparatus.

SUMMARY OF THE INVENTION AND OBJECTS The sheet-gauging apparatus forgauging properties of a sheet of material consists of a frame which hasa pair of spaced upper and lower parallel beams extending laterally ofthe sheet. Upper and lower track means are carried by the upper andlower beams respectively. Upper and lower gauging heads are providedwhich are adapted to be disposed on opposite sides of the sheet.Carriage means is provided for mounting the gauging heads on the upperand lower track means. Drive means is also provided and timing beltmeans is connected to the drive means and tothe carriage means forshifting the gauging heads longitudinally of the beams and laterally ofthe sheet of paper. Gauging means is carried by the gauging heads forsensing a property of the sheet as the heads are shifted relative to thesheet.

In general, it is an object of the present invention to provide asheet-gauging apparatus having gauging heads which are preciselypositioned with respect to each other as they are shifted relative tothe sheet being gauged.

Another object of the invention is to provide sheet-gauging apparatus ofthe above character in which track means is provided on which thegauging heads travel.

Another object of the invention is to provide a sheet-gauging apparatusof the above character in which means is provided for maintaining asubstantially uniform temperature along the track means.

Another object of the invention is to provide sheet-gauging apparatus ofthe above character in which means is provided for rotecting the trackmeans from dust, dirt and the like.

Another object of the invention is to provide sheet-gauging apparatus ofthe above character in which precision stepping means is utilized fordriving timing means for shifting the gauging heads longitudinally ofthe track means.

BRIEF DESCRIPTION OF THE DRAWING FIGS. 1A and 1B are side elevationviews with certain parts broken away of a sheet-gauging apparatusincorporating the present invention.

FIG. 2 is an end elevational view of the left-hand end of the apparatusshown in FIGS. 1A and 18 with certain parts broken away.

FIG. 3 is a cross-sectional view taken along the line 3--3 of FIG. 1B.

FIG. 4 is an end elevational view of the left-hand end of the apparatusshown in FIGS. IAand 113.

FIG. 5 is a side elevational view of the apparatus shown in FIG. 1B butshowing the opposite side with certain portions broken away.

FIG. 6 is a side elevational view of the gauging head assem blyapparatus shown in FIGS. 1A and 1B.

FIG. 7 is a cross-sectional view taken along the line 7-7 of FIG. 6.

FIG. 8 is an end elevational view of the gauging head assembly shown inFIG. 6.

FIG. 9 is a top plan view of the head assembly shown in FIG. 8.

2 DESCRIPTION OF THE PREFERRED EMBODIMENT The sheet-gauging apparatusconsists of a main frame 11. The main frame 11 consists of a pair ofspaced end supports 12 and H3 which extend generally in a verticaldirection and a pair of spaced substantially parallel I-beams 14 and 16which extend generally in a horizontal direction and are secured to theend supports 12 and 13.

For reasons hereinafter described, the end support 12 can be consideredas a drive-in support and consists of a flat vertical plate 17 which hasa vertical reinforcing web 18 secured thereto so that the end support issubstantially T shaped in cross section. A bottom pad I9 is secured tothe lower extremities of the plates 17 and 18. The end support 13 isformed of a vertical plate 21 and is provided with a pair of spacedvertical reinforcing webs 22 so that in cross section the end support 13is generally in the form of a double 'l." A horizontally disposed pad 23is secured to the lower extremities of the plates 21 and the webs 22.The pad 23 is provided with an elongaterecess 24 which is adapted toreceive a large roller 26. The recess 24 has a width which issubstantially greater than the diameter of the roller 26, as can be seenfrom FIG. 1B. The roller also seats in a similar recess 27 provided in alower pad28 which is adapted to be secured to the foundation for theapparatus by bolts. 29. The pad 19 of the end support 12 is secured to alower pad (not shown) provided by the customer by bolts 31.

The end supports 12 and 13 include parallel spaced vertical flanges 32provided on the inner surfaceof the plates 17 and 21. The l-beams M and16 are secured to the flanges 32 by bolts 33. In order to assure exactalignment, pins 34 are provided on the end-of the I-beams and areadapted to be inserted in the flanges to precisely position the l-beamsprior to tightening of the bolts 33. This arrangement permits theapparatus to be disassembled and then reassembled while still retainingthe same exact alignment.

Upper and lower track means 36 and 37 are provided and which are securedby the [beams 14 and 16. They are generally similar in construction asshown in the drawings and each consists of aflat plate 38 disposed belowthe l-beam and supported therefrom by a plurality of pairs of bolts 39which are spaced longitudinally of the plate 38 and which are securedopposite flanges (see FIG. 3) of the associated lbeam. Nuts 41 on thebolts 39 are provided for retaining the plate in the desired adjustedposition. For the apparatus to operate satisfactorily, it is desirableto have the plates 38 be as exactly level as possible and also that theyare exactly straight in a sidewise direction for the entire length ofthe main frame. Thus, it is desirable that the tolerance in a verticaldirection and also in a sideways direction be within 0.0020 of an inch.

An upper gauging head assembly 46 is carried by the upper track means 36and a lower gauging head assembly 47 is carried by the lower track means37. The head assemblies 46 and 47 are very similar and include a headhousing or casting 48 formed of suitable material, such as aluminum, andwhich is provided with a pair of spaced generally parallel ears 49. Ahead pivot plate 51 is secured to each of the ears 49 by bolts 52 whichextend through arcuate slots 53 and 54 provided in the head pivot plates51. A pair of spaced generally parallel platelike lever arms 55 arepivotally secured to the head pivot plate 51 by bolts v56 and to a leversupport plate 57 by bolts 58. The lever support plate 57 is secured tohead support castings 59 by screws 60 for the lower gauging headassembly 47. The head castings 59 are mounted upon a pad support casting61 by screws 62. For the upper gauging head assembly, the platelikelever arms 55 are directly secured to the pad support casting 611 by,screws 62. Removable pins 63 are provided which extend through theplatelike lever arms 55 and into one of the holes 70 in the head supportmember 57 and are utilized for retaining the gauging head assemblies ina predetermined angular position with respect to the sheet of paper asshown by the broken lines in FIG. 3. The pins 63 can be shifted betweenthe upper and lower holes 70 in the support member 57 to position thelever arms 55 between the solid line position shown in FIG. 3 and thebroken line position also shown in FIG. 3 to adjust the position of thegauging head assemblies 46 and 47 as hereinafter described.

As can be seen particularly from FIG. 7, the pad support casting 61 isprovided with four padlike portions 61a provided on the four comers ofthe casting. A U-shaped member 64 is secured to each of the padlikeportions 51a by bolts 65. A pair of side support wheels or rollers 66are rotatably mounted upon Teflon bearings (not shown) between each ofthe U- shaped members 64 and the pad portion 61a associated therewithand are adapted to engage the sides of the plate 38 which forms a partof the upper track means 36. Each of the U-shaped members 64 alsocarries a pair of spaced top support wheels or rollers 67 rotatablymounted thereon by suitable means such as ball bearings. It has beenfound desirable to provide rubber-tired wheels for the side supportwheels 66 and the top support wheels 67 because it may be necessary tomount the sheet-gauging apparatus in corrosive atmospheres. When such isthe case, it also is desirable to coat the upper and lower track meanswith a suitable protective covering such as an epoxy resin. Therubbertired wheels or rollers prevent the wheels or rollers fromchipping the epoxy resin off of the track means.

The lower head assembly 47 is mounted in a somewhat similar manner upona pad support casting 61 on the lower track means with the use of thehead support castings 59. The pad portions 61a carry side support wheels66 and top support wheels 67 in the same manner as for the upper headassembly so that the lower head assembly also is secured by and isguided by lower track means 37. The pad support castings 61 with theirside support rollers 66 and top support rollers 67 serve as carriagemeans for the associated head assembly for travel on the associatedtrack means.

The castings 48 are provided with passages 68 through which a coolingfluid such as water can be introduced for cooling the casting. A sheetguide plate 69 formed of suitable material such as aluminum is securedto each of the head castings 48 by suitable means such as countersunkscrews 70. As can be seen and particularly from FIG. 6, the sheet guideplate 69 is provided with upturned outer side margins 69a.

The head castings 48 have certain devices mounted thereon as hereinafterdescribed. In addition, each of the head assemblies has a water-inconnector 71, a water-out connector 72, a compressed air connector 73and a pair of electrical connectors 74 and 76.

A cover 81 formed of a suitable material such as fiberglass is providedfor each of the head assemblies 46 and 47 and is provided with a rubbermolding 82 on its outer edge which is adapted to engage the casting 48.The cover is held in place by a suitable means such as clamps 83.

Means is provided for advancing the upper gauging head assembly 46 andthe lower gauging head assembly 47 in a precision manner with respect toeach other and to the frame 11. This means consists of a bracket 86which is secured to the pad support casting 61 by suitable means such asscrews 87. A nonslip timing belt 88 having teeth 880 has its endssecured to a pair of spaced shafts 89 secured to the upper ends of thebrackets 86 by capscrews 91. The shafts 89 are provided with flats 92and have the ends of the timing belt clamped thereto by a clamping plate93 and capscrews 94. The shafts 89 have hexagonal portions 89a tofacilitate rotation of the shaft to tighten the timing belt 88.

The two timing belts 88 are driven by a main toothed drive sprocket 96(see FIG. 1A) and are rotatably mounted upon a shaft 97 carried by theend support 12. As can be seen from FIG. 2, the main drive sprocket 96is wide enough to accommodate three timing belts. Thus, it drives thetwo timing belts 88 and is driven by separate timing belt 99 that isdriven by a drive sprocket 101 mounted upon the output shaft 102 of asuitable stepper motor 103 such as a Slosyn motor manufactured by theSuperior Electric Company of Bristol, Conn. The motor 103 is mountedupon a bracket 104 by bolts 106 and the bracket 104 is secured to theend support 12 by the bolts 107.

Both of the belts 88 travel over a pair of idler rollers 108 and 109.The idler rollers 108 and 109 are rotatably mounted upon the shafts 11]mounted in shaft supports 112 secured to the end support 12 by capscrews113. The idler rollers 108 and 109 are positioned so as to guide theupper and lower runs of each of the timing belts 88 through openings 116 provided in the end support 12. The openings 116 are substantiallylarger than that required for the timing belt for the admission of airas hereinafter described. The timing belts 88 travel longitudinally ofthe I-beams l4 and 16 as shown in FIGS. 1A and 13. over small idlerrollers mounted on the I-beams l4 and 16, and over large idler rollers117 mounted upon shafts 1 18 carried by the I-beams adjacent end support13.

Means is provided for supporting the conduits and/or cables 121 whichare utilized for supplying the water, air and electrical energy insignals to the connectors 71, 72, 73, 74 and 76 for each of the upperand lower head assemblies 46 and 47 and consists of a bracket 122 whichis mounted upon the pad portions 61a by capscrews 123. The brackets 122and 86 are mounted on opposite sides of the casting. The conduits aresecured to the brackets 122 by clamps 124 and fastened thereto bycapscrews 126. The conduits 12] extend upwardly through the bracket 122and then extend into a carrier 127 of a conventional type such as thatdisclosed in U.S. Pat. Nos. 2,864,907 and 2,975,807. As is well known tothose skilled in the art, the carrier 127 is capable of supporting theconduits while accommodating the travel of the head assemblies 46 and47. Thus, the conduits extend through the upper run of the carrier 127and down through the lower run to the end support 12 where they areconnected to the appropriate exterior sources (not shown).

As shown particularly in FIG. 3, the timing belts 88 are mounted on oneside of the l-beams, whereas the carrier 127 is mounted on the otherside of the I-beam. As also shown in FIG. 3, a support channel 128 isprovided for the lower run of the carrier 127 as it is laid down. Thesupport channel 128 is carried by the lower portion of the associatedI-beam as shown in FIG. 3.

Means is provided for supplying energy to the stepper motor 103 andcontrolling its operation. Generally, the control is such that when thesheet-gauging apparatus is placed in operation, the stepper motor 103rotates in small, precise, discrete steps to advance the timing belts.It accelerates gradually to drive the head assemblies 46 and 47 acrossthe main frame 11 and then the stepper motor 103 decelerates butcontinues to move in the same direction until a vane 131 carried by thebracket 86 enters a vane oscillator switch 132 of conventional typemounted upon the l-beam 14 by bracket 133. At the same time this isoccurring, a vane 136 carried by the bracket 86 on the lower headassembly 47 enters a vane oscillator switch 137 carried by a bracket138. As soon as the vanes BI and 136 enter the vane oscillator switches132 and 137 which are adjacent the end support 13, the control circuitryassociated therewith reverses the movement of the head assemblies 46 and47 by bringing the same to a stop and gradually accelerating them tomove in an opposite direction across the main frame II. This movementcontinues until the vanes 131 and 136 enter similar vane oscillatorswitches 132 and 137 provided adjacent to the end support 12. This,again,.causes a reversal of the stepper motor 103 and reversal movementof the head assemblies 46 and 47 to cause them again to travel down themain frame in a direction towards the end support 13. This repeatedtraversing of the main frame 11 continues during operation of thesheet-gauging apparatus.

Auxiliary safety stop means is provided to prevent further movement ofthe head assemblies 46 and 47 in the event that the vane oscillatorswitches 132 and 137 fail to operate. This stop means consists of limitswitches 141 mounted upon the end supports 12 and 13 which are adaptedto be engaged by the head assemblies 46 and 47 in the event their travelis not arrested by the vane oscillator switches 132 and 137 so as toprevent damage to the entire apparatus and particularly to the headassemblies 416 and 47. Such limit switches consist of a plunger 141.7.which is mounted on a fitting 143 secured to the associated end support12 or 13 by a nut 16 1. A rubber bumper 1416 is mounted over the plunger1 1.2. The plunger is adapted to engage a microswitch 1 17 carried bybracket 1413. The bracket 166 and the switch 167 are protected by a dustcover M9.

Elongate covers 156 and 157, which are substantially U shaped in crosssection as shown in P10. 3, are mounted over the upper and lower I-beamsM and 16 and extend the entire length of the ll-bearns between the endsupports 12 and 13. The covers 136 and 157 also cover the upper trackmeans 36 and the lower track means 37. As can be seen from FIG. 3, thelower extremities of the covers 156 and 157 are laterally spaced fromthe outer margins of the plates 36 which form a part of the upper trackmeans 36 and the lower track means 37.

A large end cover 161 is mounted on the end support 12 and is providedwith an upper section 161a and a lower section 1611b. The lower section16112 is secured to the end sup port 13 by brackets 16?; and the uppersection 161a is removably secured to the end support 12 by clamps 163.The upper section 161a of the end cover 161 is provided with a largeframed opening 166 which has mounted therein a large filter 163. A pairof spaced fans 171 are mounted within the upper section 161a immediatelybehind the filter 163 and draw air through the filter 163, forcing itthrough the openings 116 in the end support into the covers 156 and 157.The air in troduced into the covers 156 and 157 travels longitudinallyof the [-beams 16 and 16 and gradually discharges downwardly through thespaces provided between the lower ends of the covers 156 and 157 and theplates 36 forming parts of the upper track means 36 and lower trackmeans 37.

A cover 176 also formed of a suitable material such as im pregnatedfiberglass is mounted upon the end support 13 so that the appearance ofthe end support 13 is similar to the end support 12.

As hereinbefore indicated, certain devices are mounted in the upper headassembly 16 and the lower head assembly 47 which are useful for sheetgauging. Thus, for example, the lower head assembly 66 can contain aradiation source 181 of the type described in copending application Ser.No. 792,088, filed Jan. 17, 1969 in the event that basis weightmeasurements are to be made. A power supply 162 of a conventional typeis mounted within the head assembly. If moisture measurements are to bemade, an infrared source 163 of a type described in copendingapplication Ser. No. 799,784, filed Feb. 17, 1969 can be utilized.

When the above-identified measurements are to be made, a basis weightgauge detector assembly 136 of the type described in copendingapplication Ser, No. 791,915, filed Jan. 17, 1969 is provided in theupper head assembly 16. A power supply of a conventional type 1117 isalso provided in the upper head assembly. A moisture detector 166 of aconventional type can also be provided in the upper head assembly. Theradiation source 161 and the basis weight gauge detector assembly 166are arranged so they are opposite each other and so that the radiationfrom the radiation source travels through the sheet of paper indicatedat 191 to the basis weight gauge detector assembly. Similarly, theradiation from the infrared source 163 is positioned so the radiationtherefrom travels through the sheet 191 to the moisture detector 133.

in operation of the sheet-gauging apparatus, the sheet travels throughthe large Otype frame 11 between the upper head assembly 16 and thelower head assembly 17. The sheet being gauged is normally advancedcontinuously, and during this time the head assemblies 66 and 17 traveltransversely of the sheet. As explained previously, the head assemblies46 and d7 reciprocate longitudinally of the frame 11 and, therefore,travel back and forth in a lateral direction across the sheet 191 whichis travelling through the main frame. During this travel of the headassemblies 46 and 67, the desired measurements are being made by thedevices within the head assemblies 416 and 67.

As explained previously, the main frame 11 and the upper and lower trackmeans 36 and 37 are constructed in a very precise manner so that thehead assemblies 46 and 67 travel in a fixed relationship with respect toeach other as they move longitudinally of the main frame. As it can beseen, considerable efiort has been made to maintain the upper trackmeans 36 and lower track means 37 and the l-beams 14 and 16 which carrythe same relatively stable in temperature so that there is no change inthe relative positioning of the head assembly because of temperaturechanges. Thus, although the sheet 191 travelling through the apparatusand being gauged may be very hot, precise measurements are still made.The sheet guide plates 66 serve as radiant heat shields and the heatsupport castings 63 are water cooled so that the electronic devicesmounted within the head assemblies 46 and 67 remain relatively cool.

At the same time that water cooling is being utilized for the headassemblies 46 and 417, the upper and lower track means 36 and 37 arebeing continuously cooled by the stream of air passing longitudinally ofthe l-beams from the fans 171 provided in the end support 12. Thisserves to stabilize the temperature of the ]-beams and the upper trackmeans 36 and the lower track means 37 along their entire length. Thisserves to retain the desired spacing between the head assemblies 16 and17 as they traverse the main frame. The covers 156 and 157 covering the]-beams, in addition to providing channels for the passage of air forcooling of the l-beams, also serve to protect the upper and lower trackmeans 36 and 37 by keeping dust, dirt and the like off of the tracks. Inaddition, the slight overpressure created in the covers 156 and 157 byintroducing air into the covers 156 and 157 prevents corrosive vaporsand the like from coming into contact with the upper and lower trackmeans.

The covers 81 provided as a part of the head assemblies 46 and 47 haverelatively smooth surfaces so that in the event the sheet travellingthrough the apparatus should strike the same, the sheet will not betorn. The covers 81 also serve as a shield against heat radiating fromthe sheet being gauged to protect the electronic devices within the headassemblies. in addition, the covers prevent the entrance of dust, dirtand the like into the head assemblies.

The upper and lower gauging head assemblies 46 and 47 are mounted uponthe carriage means in such a manner so that any radiation introducedthrough the sheet by the devices carried by the head assemblies 46 and17 passes through the sheet substantially perpendicular regardless ofthe inclination of the sheet relative to the main frame. It can beappreciated that this is important so that the measurements are made inthe same position with respect to the sheet being gauged. As can be seenfrom H6. 3, the head assemblies 16 and 47 can be adjusted throughsubstantial angles. First, the positions of the lever arms 55 can beadjusted between two positions by shifting the pins 63 from the positionshown in FIG. 3 to the upper holes provided in the support member 57.Additional, more precise adjustment can be accomplished by shifting ofthe pivot plates 51 and then tightening the bolts 52. in this way, it ispossible to accommodate the various paths of travel for the sheetthrough the main frame while still maintaining the head assemblies 46and 47 and the radiation passing therebetween substantiallyperpendicular to the sheet passing through the main frame.

It is apparent from the foregoing that there has been provided a new andimproved apparatus for the gauging ofsheets. The apparatus isparticularly of a precision type which can be utilized for making aplurality of precision measurements at many different positions onsheets of material which are moving continuously.

I claim:

1. in a sheet-gauging apparatus for gauging properties of a sheet ofmaterial, a frame having parallel-spaced, upper and lower beamsextending laterally of the sheet, spaced upper and lower track meanscarried by the upper and lower beams, upper and lower gauging headassemblies disposed on opposite sides of the sheet, upper and lowercarriage means mounting said upper and lower gauging head assemblies onsaid upper and lower track means, motor drive means and nonslip timingbelt means connected to said motor drive means and to said carriagemeans for shifting said gauging head assemblies longitudinally of thebeams and laterally of the sheet, said nonslip timing belt meansincluding a flexible belt having toothlike portions formed thereinextending transversely of the belt and pulleys engaged by the belt andhaving recesses therein extending axially of the pulleys for receivingthe toothlike portions and gauging means carried by said upper and lowergauging head assemblies for gauging a property of said sheet as theheads are shifted longitudinally of the beams.

2. Apparatus as in claim 1 together with means for mounting said frameon a foundation and means carried by at least one end of said framepermitting shifting of one end of the frame with respect to thefoundation to accommodate expansion and contraction of the frame.

3. Apparatus as in claim 1 wherein said upper and lower track means eachincludes a plate extending the length of the frame and having at leastone flat surface extending the length of the frame and wherein saidcarriage means includes roller means travelling on said surface.

4. In a sheet-gauging apparatus for gauging properties of a sheet ofmaterial, a frame having parallel-spaced, upper and lower beamsextending laterally of the sheet, spaced upper and lower track meanscarried by the upper and lower beams, cover means for protecting saidupper and lower track means, means for introducing cooling air into thecover means to maintain said upper and lower track means at asubstantially uniform temperature, upper and lower gauging headassemblies disposed on opposite sides of the sheet, upper and lowercarriage means mounting said upper and lower gauging head assemblies onsaid upper and lower track means, motor drive means connected to saidcarriage means for shifting said gauging head assemblies longitudinallyof the beams and laterally of the sheet, and gauging means carried bysaid upper and lower head assemblies for gauging a property of saidsheet as the heads are shifted longitudinally of the beam.

5, Apparatus as in claim 4 wherein said covers are mounted on said upperand lower beams and cover the upper and lower track means, said covermeans having lower extremities spaced from the track means, and meansfor introducing cooling air into the cover and for causing it todischarge downwardly through the space between the track means and thelower extremities of the cover along the entire length of the trackmeans to thereby maintain said track means at a substantially uniformtemperature throughout their lengths.

6. Apparatus as in claim 5 wherein said means for preventing movement ofsaid gauging head assemblies beyond predetermined spaced points on saidbeams includes a conducting vane and a vane-type oscillator adapted toreceive said vane.

7. In a sheet-gauging apparatus for gauging properties of a sheet ofmaterial, a frame having parallel-spaced, upper and lower beamsextending laterally of the sheet, spaced upper and lower elongatedplatelike track means carried by the upper and lower beams, adjustablemeans for mounting said upper and lower elongated platelike track meansupon said upper and lower beams whereby each of said track means can beadjusted laterally and longitudinally so that they are level throughouttheir entire length, upper and lower gauging head assemblies disposed onopposite sides of the sheet, upper and lower carriage means mountingsaid upper and lower gauging head assemblies on said upper and lowertrack means, motor drive means connected to said carriage means forshifting said gauging head assemblies longitudinally of the beams andlaterally of the sheet, and gauging means carried by said upper andlower gauging head assemblies for gauging a property of said sheet asthe heads are shifted longitudinally of the beams.

8. In a sheet-gauging apparatus for gauging properties of a sheet ofmaterial, a frame having parallel-spaced, upper and lower beamsextending laterally of the sheet, spaced upper and lower track meanscarried by the upper and lower beams, upper and lower gauging headassemblies disposed on opposite sides of the sheet, upper and lowercarriage means mounting said upper and lower gauging head assemblies onsaid upper and lower track means, motor drive means connected to saidcarriage means for shifting said gauging head assemblies longitudinallyof the beams and laterally of the sheet, gauging means carried by saidupper and lower gauging head assemblies for gauging a property of saidsheet as the heads are shifted longitudinally of the beams, said upperand lower gauging head assemblies including a housing, said housinghaving a passage therein for the travel of a cooling fluid therethrough,and a sheet guide mounted on said housing, said sheet guide havinginclined outer side margins which are inclined away from the sheettravelling between the gauging head assemblies.

9. In a sheet-gauging apparatus for gauging properties of a sheet ofmaterial, a frame having parallel-spaced, upper and lower beamsextending laterally of the sheet, spaced upper and lower track meanscarried by the upper and lower beams, upper and lower gauging headassemblies disposed on opposite sides of the sheet, upper and lowercarriage means mounting said upper and lower gauging head assemblies onsaid upper and lower track means, motor drive means and nonslip timingbelt means connected to said drive means and to said carriage means forshifting said gauging head assemblies longitudinally of the beams andlaterally of the sheet, and gauging means carried by said upper andlower gauging head assemblies for gauging a property of said sheet asthe heads are shifted longitudinally of the beams, said gauging meanscarried by said upper and lower gauging head assemblies including meansfor introducing radiation through said sheet and means for adjusting thepositions of the upper and lower gauging head assemblies so that theradiation passing through the sheet is maintained perpendicular to thesheet regardless of the inclination of the sheet relative to the upperand lower track means of the frame.

10. In a sheet-gauging apparatus for gauging properties of a sheet ofmaterial, a frame having parallel-spaced, upper and lower beamsextending laterally of the sheet, spaced upper and lower track meanscarried by the upper and lower beams, upper and lower gauging headassemblies disposed on opposite sides of the sheet, upper and lowercarriage means mounting said upper and lower gauging head assemblies onsaid upper and lower track means, motor drive means connected to saidcarriage means for shifting said gauging head assemblies longitudinallyof the beams and laterally of the sheet, gauging means carried by saidupper and lower gauging head assemblies for gauging a property of saidsheet as the heads are shifted longitudinally of the beams, said gaugingmeans including means for introducing radiation through said sheet andmeans for adjusting the positions of the upper and lower gauging headassemblies so that the radiation passing through the sheet is maintainedperpendicular to the sheet regardless of the inclination of the sheetrelative to the upper and lower track means of the frame, said means foradjusting the positions of the upper and lower gauging head assembliesincluding a housing, a pair of pivot plates, cooperative means carriedby the pivot plates and the housing for mounting said pivot plates onsaid housing and permitting movement of said pivot plates through apredetermined angle, a pair of lever arms pivotally secured to each ofsaid pivot plates, means pivotally connecting said lever arms to saidcarriage means, and means for adjusting the position of said lever armson said carriage means whereby the position of said gauging headassemblies can be adjusted.

11. in a sheet-gauging apparatus for gauging properties of a sheet ofmaterial, a frame having parallel-spaced upper and lower beams extendinglaterally of the sheet, spaced upper and lower track means carried bythe upper and lower beams, upper and lower carriage means mounted onsaid upper and lower track means, upper and lower gauging headassemblies disposed on opposite sides of the sheet, and means formounting said upper and lower gauging head assemblies on said upper andlower carriage means, said gaug'ng head assemblies including means forintroducing radiation through the sheet of material, said adjustablemeans for mounting each of said upper and lower gauging head assemblieson said upper and lower carriage means including a pair of pivot plates,cooperative means carried by the pivot plates and by the gauging headassembly for mounting said pivot plates on the gauging head assembly andpermitting limited pivotal movement of the pivot plate with respect tothe gauging head assembly, a pair of pivot arms pivotally connected tosaid pivot plate, and means pivotally connecting said pivot arms to saidcarriage means and means for adjusting the angular position of saidpivot arms on said carriage means whereby said gauging head assembliescan be adjusted so that the radiation extending through the sheet ofmaterial is substantially perpendicular to the sheet regardless of theinclination of the sheet.

B2. In a sheet-gauging apparatus for gauging properties of a sheet ofmaterial, a frame having parallel-spaced upper and lower beams extendinglaterally of the sheet, spaced upper and lower track means carried bythe upper and lower beams, upper and lower gauging head assembliesdisposed on opposite sides of the sheet, upper and lower carriage meansmounting said upper and lower gauging head assemblies on said upper andlower track means. and drive means for moving said carriage means andsaid gauging head assemblies longitudinally of the beams and laterallyof the sheet, covers mounted on said beams and covering said upper andlower track means, and means for introducing air into the cover meansand to cause the same to pass over the entire length of the upper andlower track means whereby the upper and lower track means are maintainedat a substantially uniform temperature throughout their lengths.

113. Apparatus as in claim 12 wherein said covers have lower extremitiesand wherein the lower extremities of the covers are spaced from thetrack means whereby air introduced into the covers can dischargedownwardly between the track means and the lower extremities of thecovers.

1. In a sheet-gauging apparatus for gauging properties of a sheet ofmaterial, a frame having parallel-spaced, upper and lower beamsextending laterally of the sheet, spaced upper and lower track meanscarried by the upper and lower beams, upper and lower gauging headassemblies disposed on opposite sides of the sheet, upper and lowercarriage means mounting said upper and lower gauging head assemblies onsaid upper and lower track means, motor drive means and nonslip timingbelt means connected to said motor drive means and to said carriagemeans for shifting said gauging head assemblies longitudinally of thebeams and laterally of the sheet, said nonslip timing belt meansincluding a flexible belt having toothlike portions formed thereinextending transversely of the belt and pulleys engaged by the belt andhaving recesses therein extending axially of the pulleys for receivingthe toothlike portions and gauging means carried by said upper and lowergauging head assemblies for gauging a property of said sheet as theheads are shifted longitudinally of the beams.
 2. Apparatus as in claim1 together with means for mounting said frame on a foundation and meanscarried by at least one end of said frame permitting shifting of one endof the frame with respect to the foundation to accommodate expansion andcontraction of the frame.
 3. Apparatus as in claim 1 wherein said upperand lower track means each includes a plate extending the length of theframe and having at least one flat surface extending the length of theframe and wherein said carriage means includes roller means travellingon said surface.
 4. In a sheet-gauging apparatus for gauging propertiesof a sheet of material, a frame having parallel-spaced, upper and lowerbeams extending laterally of the sheet, spaced upper and lower trackmeans carried by the upper and lower beams, cover means for protectingsaid upper and lower track means, means for introducing cooling air intothe cover means to maintain said upper and lower track means at asubstantially uniform temperature, upper and lower gauging headassemblies disposed on opposite sides of the sheet, upper and lowercarriage means mounting said upper and lower gauging head assemblies onsaid upper and lower track means, motor drive means connected to saidcarriage means for shifting said gauging head assemblies longitudinallyof the beams and laterally of the sheet, and gauging means carried bysaid upper and lower head assemblies for gauging a property of saidsheet as the heads are shifted longitudinally of the beam.
 5. Apparatusas in claim 4 wheRein said covers are mounted on said upper and lowerbeams and cover the upper and lower track means, said cover means havinglower extremities spaced from the track means, and means for introducingcooling air into the cover and for causing it to discharge downwardlythrough the space between the track means and the lower extremities ofthe cover along the entire length of the track means to thereby maintainsaid track means at a substantially uniform temperature throughout theirlengths.
 6. Apparatus as in claim 5 wherein said means for preventingmovement of said gauging head assemblies beyond predetermined spacedpoints on said beams includes a conducting vane and a vane-typeoscillator adapted to receive said vane.
 7. In a sheet-gauging apparatusfor gauging properties of a sheet of material, a frame havingparallel-spaced, upper and lower beams extending laterally of the sheet,spaced upper and lower elongated platelike track means carried by theupper and lower beams, adjustable means for mounting said upper andlower elongated platelike track means upon said upper and lower beamswhereby each of said track means can be adjusted laterally andlongitudinally so that they are level throughout their entire length,upper and lower gauging head assemblies disposed on opposite sides ofthe sheet, upper and lower carriage means mounting said upper and lowergauging head assemblies on said upper and lower track means, motor drivemeans connected to said carriage means for shifting said gauging headassemblies longitudinally of the beams and laterally of the sheet, andgauging means carried by said upper and lower gauging head assembliesfor gauging a property of said sheet as the heads are shiftedlongitudinally of the beams.
 8. In a sheet-gauging apparatus for gaugingproperties of a sheet of material, a frame having parallel-spaced, upperand lower beams extending laterally of the sheet, spaced upper and lowertrack means carried by the upper and lower beams, upper and lowergauging head assemblies disposed on opposite sides of the sheet, upperand lower carriage means mounting said upper and lower gauging headassemblies on said upper and lower track means, motor drive meansconnected to said carriage means for shifting said gauging headassemblies longitudinally of the beams and laterally of the sheet,gauging means carried by said upper and lower gauging head assembliesfor gauging a property of said sheet as the heads are shiftedlongitudinally of the beams, said upper and lower gauging headassemblies including a housing, said housing having a passage thereinfor the travel of a cooling fluid therethrough, and a sheet guidemounted on said housing, said sheet guide having inclined outer sidemargins which are inclined away from the sheet travelling between thegauging head assemblies.
 9. In a sheet-gauging apparatus for gaugingproperties of a sheet of material, a frame having parallel-spaced, upperand lower beams extending laterally of the sheet, spaced upper and lowertrack means carried by the upper and lower beams, upper and lowergauging head assemblies disposed on opposite sides of the sheet, upperand lower carriage means mounting said upper and lower gauging headassemblies on said upper and lower track means, motor drive means andnonslip timing belt means connected to said drive means and to saidcarriage means for shifting said gauging head assemblies longitudinallyof the beams and laterally of the sheet, and gauging means carried bysaid upper and lower gauging head assemblies for gauging a property ofsaid sheet as the heads are shifted longitudinally of the beams, saidgauging means carried by said upper and lower gauging head assembliesincluding means for introducing radiation through said sheet and meansfor adjusting the positions of the upper and lower gauging headassemblies so that the radiation passing through the sheet is maintainedperpendicular to the sheet regardless of the inclination of the sheetrelative to the upper and lower track means of the frame.
 10. In asheet-gauging apparatus for gauging properties of a sheet of material, aframe having parallel-spaced, upper and lower beams extending laterallyof the sheet, spaced upper and lower track means carried by the upperand lower beams, upper and lower gauging head assemblies disposed onopposite sides of the sheet, upper and lower carriage means mountingsaid upper and lower gauging head assemblies on said upper and lowertrack means, motor drive means connected to said carriage means forshifting said gauging head assemblies longitudinally of the beams andlaterally of the sheet, gauging means carried by said upper and lowergauging head assemblies for gauging a property of said sheet as theheads are shifted longitudinally of the beams, said gauging meansincluding means for introducing radiation through said sheet and meansfor adjusting the positions of the upper and lower gauging headassemblies so that the radiation passing through the sheet is maintainedperpendicular to the sheet regardless of the inclination of the sheetrelative to the upper and lower track means of the frame, said means foradjusting the positions of the upper and lower gauging head assembliesincluding a housing, a pair of pivot plates, cooperative means carriedby the pivot plates and the housing for mounting said pivot plates onsaid housing and permitting movement of said pivot plates through apredetermined angle, a pair of lever arms pivotally secured to each ofsaid pivot plates, means pivotally connecting said lever arms to saidcarriage means, and means for adjusting the position of said lever armson said carriage means whereby the position of said gauging headassemblies can be adjusted.
 11. In a sheet-gauging apparatus for gaugingproperties of a sheet of material, a frame having parallel-spaced upperand lower beams extending laterally of the sheet, spaced upper and lowertrack means carried by the upper and lower beams, upper and lowercarriage means mounted on said upper and lower track means, upper andlower gauging head assemblies disposed on opposite sides of the sheet,and means for mounting said upper and lower gauging head assemblies onsaid upper and lower carriage means, said gauging head assembliesincluding means for introducing radiation through the sheet of material,said adjustable means for mounting each of said upper and lower gauginghead assemblies on said upper and lower carriage means including a pairof pivot plates, cooperative means carried by the pivot plates and bythe gauging head assembly for mounting said pivot plates on the gauginghead assembly and permitting limited pivotal movement of the pivot platewith respect to the gauging head assembly, a pair of pivot armspivotally connected to said pivot plate, and means pivotally connectingsaid pivot arms to said carriage means and means for adjusting theangular position of said pivot arms on said carriage means whereby saidgauging head assemblies can be adjusted so that the radiation extendingthrough the sheet of material is substantially perpendicular to thesheet regardless of the inclination of the sheet.
 12. In a sheet-gaugingapparatus for gauging properties of a sheet of material, a frame havingparallel-spaced upper and lower beams extending laterally of the sheet,spaced upper and lower track means carried by the upper and lower beams,upper and lower gauging head assemblies disposed on opposite sides ofthe sheet, upper and lower carriage means mounting said upper and lowergauging head assemblies on said upper and lower track means, and drivemeans for moving said carriage means and said gauging head assemblieslongitudinally of the beams and laterally of the sheet, covers mountedon said beams and covering said upper and lower track means, and meansfor introducing air into the cover means and to cause the same to passover the entire length of the upper and lower track means whereby theupper and lower track means are maintained at a substantially unifOrmtemperature throughout their lengths.
 13. Apparatus as in claim 12wherein said covers have lower extremities and wherein the lowerextremities of the covers are spaced from the track means whereby airintroduced into the covers can discharge downwardly between the trackmeans and the lower extremities of the covers.